1. Field
Embodiments of the present invention relate to a secondary battery.
2. Description of the Related Art
Unlike primary batteries, which cannot be recharged, secondary batteries can be repeatedly charged and discharged. A low capacity secondary battery that uses a single battery cell packaged in a battery pack is used as a power source for various portable small-sized electronic devices such as cellular phones, and camcorders. A high capacity secondary battery that uses tens of battery cells connected to each other in a battery pack is widely used as a power source for driving motors such as in electric scooters, or hybrid electric vehicles (HEV).
Secondary batteries may be classified into different types, for example, cylindrical and prismatic types. A unit battery includes an electrode assembly having positive and negative electrodes and a separator located between the positive and negative electrodes, a case for receiving the electrode assembly with an electrolyte, and a cap assembly having an electrode terminal installed in the case.
Occasionally, the secondary battery may undergo fire or explosion due to an increase in the internal pressure when excessive heat is generated due to overcharge or an electrolyte is decomposed. Accordingly, there is a need for a secondary battery capable of improved safety.